Time switch assembly



Aug-18,1959 w. J.Ksc1'l vULTz ETAL 4 2,900,463

TIME SWITCH ASSEMBLY Filed Nov. 18, 1957 2 sheets-sheet z llnvenfors 1William J. Schuiiz Curl F. Von Bennekom United States Patent O TIMESWITCH ASSElVIBLY William J. Schultz and Carl F. van Bennekom, Lynnield,

Mass., assignors to General Electric Company, a corporation of New YorkApplication November 18, 1957, Serial No. 697,206

Claims. (Cl. 200-38) This invention pertains to time switches and moreparticularly to an improved assembly for a time switch that canautomatically and regularly control electric circuits on =a schedulerelated to the time of day.

Such time switches normally include a pair of contact spring blades.operable to open and closed switching positions by a switch operatormechanism adapted to be operated at preselected times according to aschedule of operations by a plurality of :actuators movable in sequenceIinto operative engagement with the switch operator mechanism. Theschedule of switch operations is established by arranging actuators on arotatable calibrated dial member |which is operated in a timed manner bya suitable driving mechanism such as a synchronous motor and reductiongear.

In assemblies of such time switches, it has been customary to mount theoperating elements on a support plate which in turn may be mounted in abox-type housing for installation at a control station where it is ineasy access for manual settings and maintenance. For purposes ofconvenience and safety, the calibrated dial member and switch elementsare generally mounted on opposite sides of the mounting boards, thecalibrator dial being on the front side where it is easily accessiblefor adjustmentand reading of the settings of the actuators. For purposesof accuracy and reliability, the switch elements are operated in a snapacting manner. Heretofore, switch operating mechanisms which couldeifectuate an operative connection between the switch blades and theactuators on the calibrated dial to produce switch operations in a snapacting manner have been unduly complicated and have often been made froma multiplicity of operating parts. A consequence of the complicatednature of such switch operating mechanisms has been to impose arelatively high torque load on the drive mechanism when the actuatorelement carried by the calibrated dial isbrought into engagement withthe switch operator to effectuate switching. On the other hand, duringintervals between such switch operations, as established by apredetermined schedule, a relatively low torque is required since thecalibrated dial member and the actuators represent the only load on thedrive mechanism. Thus, an appropriately sized drive mechanism `formeeting the high torque `demand often exceeded the low torque 'demand by`a considerable degree. Such a disparity presented undesirablecostliness of manufacture since it required large size operatingelements. A further consequence of a complicated switch operatingmechanism has been the introduction into quantity production of suchswitches, under normal methods of manufacture and assembly, considerableopportunities for misalignments and concomitant inaccurate operation aswell as possible malfunctioning. Significant solutions to these problemshave heretofore involved increased cost and relduced likelihood of therealization of successful quantity production at reasonable costs.

It is therefore `an object of this invention to provide a new andimproved Itme'switch having a new and im- 2 proved assembly particularlysuitable for low cost quantity manufacture and having a reduced numberof parts resulting in increased reliability, simplicity, and eciency ofoperation.

It is also an object of this invention to provide a new and improvedtime switch assembly having reduced disparity in loading of the drivemechanism in operation of the switch.

In accordance with this invention, a time switch assembly is provided inwhich a unitary switch operator is designed to be directly engageablewith both the spaced `actuator elements carried by a rotatable timeoperated dial upon one side of a support plate and deflectable switchelements on the opposite side thereof. In the preferred embodiment, theswitch operator is cylindrical and has cam means integral with andradiating from the peripheral surface thereof. Supporting the switchoperator in its `operative position so as to make possible the directengagement of the cam means with the actuator elements and switchelements is a stationary shaft positioned within an enlarged opening inthe support plate. The shaft in turn has one end fixedly attached to abridge member which is preferably concavo-convex in shape and spans theopening on one side of the plate to which it is attached. In thepreferred embodiment, the shaft is integral with the bridge member whichin turn is integral with the support plate. When given thisconstruction, the shaft, bridge member, and support plate, beingintegral, form a unitary piece to provide fixed positioning and rigidsupport. Attached to the free end of the shaft is a means for retainingthe unitary operator in operating position. Since, in the preferredembodiment, the switch elements are resilient blades bearing on one sideof the operator they exert -a counterrotary torque. To opposecounterrotation of the switch operator, the retaining means is designedto bear against the end of the switch operator. To offer increasedresistance to counterrotation, the end of the switch operator isprovided with circumferentially disposed recesses and the `retainingmeans is made in the form of a resilient blade or plate biased intoengagement with the end of the cylindrical operator and having aprotrusion therein for riding into and out of the said recesses as theoperator is rotated on the shaft.

Thus, it can be appreciated that an improved time switch has beenprovided having a simplified operation mechanism for improving switchoperating efficiency. It will also be appreciated that a new andimproved time switch `assembly has been provided which is particularlysuitable for low cost quantity manufacture and has a reduced number ofparts resulting in -a simplification of the operation of the timeswitch. A unitary switch operator having integral cam means on the outersurface thereof may be castor molded thereby permitting accurate andfixed positioning of cam surfaces. The shaft and bridge member beingattached to each other and the bridge member being attached to thesupport plate makes possible a molding or casting of a support memberwhich is completely unitary. Thus, the positioning of the parts to beoperative to perform a switching function can be accurately controlledWithout undue emphasis on close manufacturing tolerances. In addition, afurther simplication is achieved by providing a free end shaft supportto which may be attached a retaining means which can also function as anantirotation mechanism.

The featuresof this invention which are believed to be novel are setforth in the appended claims while further important `aspects andfeatures as well as objects and advantages will -be more readilyunderstood by a reference to the following detailed description anddrawings in which:

Figure 1 is a front elevation showing the time switch assembly mountedin position within an enclosing case.

Figure 2 is a left side elevation of the time switch assembly of Figurel without the enclosing case.

Figure 3 is a rear elevation of the time switch assembly of Figure lwithout the enclosing case and with certain operating elementseliminated for clarity of description.

Figure 4 is a fragmentary section taken along line 4 4 in Figure 1.

Figure 5 is a perspective view of the unitary switch operator.

Referring to the drawing, there will be seen particularly in Figures l,2, and 3, a time switch assembly incorporating the features of thisinvention which in a preferred embodiment comprises a support plate 1@having an enlarged opening 1'1 permitting through access to the frontand rear sides of the plate. Spanning the opening 11 on the front sideof plate 10 is a bridge member 12 preferably integral with the plate.Extending rearwardly through opening 11 and substantially centrallydisposed therewithin is stationary shaft support 13 which in cantileverfashion has one end xed to bridge member 12 while the opposite end isIfreely extended beyond the rear side of plate member (see particularlyFigure 4).

Mounted on support member or plate 10 and extending along the rearsurface thereof is a switch in the form of a pair of paralleldeflectable resilient blade members 14 and 15, having suitable contacts16 and 17 thereon. While any satisfactory technique or arrangement forfastening blades 14 and 15 to support plate 10 may be practiced, it ispreferred that plate 10 -be provided with an integral terminal board onthe bottom edge thereof and that this support be shaped to providerecesses in which blades 14 and 15 are individually anchored atcorresponding ends. In accordance with the preferred practice, blades 14and 15 are fabricated from suitable resilient material to have integralflanged portions on their ends designed to wrap around the end of andengage opposite sides of the terminal board and to be anchored theretoby eyelet rivets 18 which transiix the flanged portions of the blademembers in place in a manner more fully described in the copendingapplication of Warren N. Kernander and Carl F. Van Bennekom, led Iuly19, 1956, having Serial No. 598,951, and assigned to the same assigneeas the present application. Terminal screws 19 are provided forattaching electrical conductors 20 -directly to blades 14 and 15 therebyconnecting the switch into the electric circuit to be controlled. Case21 may be provided with suitable insulating bushings 22 and 23 insertedin openings in case 21 to provide passage of conductors 20 through thecasing into the area of the terminal boards. Plate member 10 may be alsoprovided with hinge abutments 24 and 25 along an edge thereof which areremovably tted to form a hinge connection with the side of case 20. Onthe opposite side of case 21, a latch member 26 is attached thereto toengage the edge of support member 10 proximate to that edge of case 21.

Substantially parallel with stationary shaft 13 is rotatable shaft 27mounted within appropriate bearing means 28 (see Figure 3) in supportplate `10. On the front side of support plate 10 calibrated dial 29 isattached by suitable screw means 30 to one end of rotatable shaft 27 soas to be rotatable therewith. Timed operation of the calibrated dial 29is obtained through the operation of a suitable constant speed electricdrive including a synchronous electric motor 31 having suitableconductor leads 32 for connection to a power supply (not shown) andreduction gearing 33 including a driven gear 34 xedly attached to theopposite end of rotatable shaft 27 (see Figure 2). Attached to thecalibrated dial 29 in selectable position on the front face thereof areactuator elements 35 and 36 generally shaped to extend radially beyondthe end of dial 29 so as to enter into the realm defined by theconcavity of bridge member 12. In addition, actuator elements 35 and 36are designed to have their extensions displaced axially in planesparallel to each other. In accordance with well-known switch operations,actuator element 35 may be designated an on actuator while actuator 36may be designated an off actuator. The time of day when such operationsoccur, of course, is determinable by setting of actuator elements 35 and36 at calibrated positions on the face of dial 29. For adjustableattachment of the actuator elements to dial 29 actuator elements 35 and36 are designed to span the dial 29 and to have setscrews 37 and 38,respectively, grip the dial. In a preferred manner, dial 29 may beprovided with a groove 39 in the face thereof for receiving the end ofsetscrews 37 and 38 thereby enhancing the gripping action to more firmlyx the actuators in their set positions.

Direct operative connection between actuator elements 35 and 36 andswitch blades 14 and 15 is obtained through a unitary switch operator 40which in its preferred embodiment is cylindrical in shape and has anaxial opening 41 therethrough for mounting on stationary shaft support13. The outer peripheral surface of operator 40 is provided with sets oflongitudinally disposed actuator cams 42 and 43 and operator cams 44.For periodically and alternately engaging actuator elements 35 and 36 asthey are carried by rotatable dial 29 actuator cams 42 and 43 arearranged in parallel planes transverse to the operator 40 and theindividual cams of the respective actuator cam sets are angularly offsetfrom each other. Longitudinally displaced from actuator cams 42 and 43are operator cams 44formed on the outer peripheral surface of operator40 and circumferentially spaced and contoured to effectuate relativedeflections of switch blades 14 and 15 to obtain snap action switching.

In its operative position, switch operator 40 is rotatably mounted onstationary shaft support 13 so as to be within opening 11 of supportplate 10. Actuator cams 42 and 43 are thereby within the concavityafforded by bridge member 12 and are consequently positioned in linewith actuator elements 35 and 36 to be periodically engaged thereby.Operator cams 44 are designed to extend longitudinally to a degree suchthat operative engagement is made with switch blades 14 and 15.Maintaining switch operator 40 in operative position on shaft support 13is a retaining means preferably formed of a resilient blade 45, one endof which is attached to the free end of stationary shaft support 13 by asuitable screw 46 removably turned into a threaded opening in the end ofshaft support 13. Resilient blade 45 is so designed as to bear againstthe end of operator 40 in the annular region between opening 41 and thebase of cams 44. Resistance to counterrotation caused by counter-rotarytorque applied to operator 40 through the bias force exerted by switchIblades 14 and 15 is thereby achieved. Further increase of thisresistance to counterrotation is obtained by forming a plurality ofcircumferentially disposed recesses 47 in the end of operator 40 andproviding a protrusion 48 on the end of resilient blade 4S.

Prior to initiation of operation, on and olf actuator elements 35 and 36are adjustably set to suitable positions on dial member 29 and switchoperator 40 is rotated manually to bring the proper actuator cam intoposition' to meet the actuator cam designed to engage it. Uponenergization of motor 31, such as by closing a manually operated switchin the circuit of the motor leads 32, motor 31 begins rotating at afixed rate of speed. Gear train 33 and particularly gear 34 `are thendriven at the constant rate, the speed of the motor being reduced bysuitable selection of the individual gears in train 33 to produce onecomplete revolution for every twenty hours for gear 34 and, hence, dialmember 29. In its rotation on shaft 27, dial member 29 carries actuatormembers 35 and 36 in circular paths until they alt ternately are broughtinto the realm of bridge member 12 to engage the actuator cams 35 and36. Assuming actuator 35 is an on actuator and actuator 36 is an oactuator and actuator cams 42 and 43 are on and off cams, respectively,actuator 35 having passed through the realm of bridge member 12 as shownin Figure 1 will have engaged one of the actuator cams 42 causing it torotatea fraction of a complete turn. Operator cams 44 and actuator cams42, being integral parts of the operator 40, will be rotated equivalentangular amounts. Operator lcams 44, due to their circumferentialdisposition along the peripheral surface of operator 40 and theircontouring, will have moved an amount to permit blade 15 to drop olf aleading cam surface to bring contact 17 into engagement with contact 16of blade 14, blade 14 being moved forward by the rotation of operator 40by a trailing cam 44. Due to the resilient nature of the blade, the dropoff produces snap action in switching. At the same time that operatorcams 44 are deflecting blades 14 and 15 to a switching position,actuator cam 43, by proper angular displacement from actuator cams 42,will be moved angularly into position to meet the radial extension ofoff actuator 36.

Continued rotation of dial member 29 brings olf actuator 36 along itscircular path and into the realm of the bridge member 12. Because oactuator 36 extends axially farther than actuator 35, it will move in aplane coincident with the plane of actuator cams 43. Thus, off actuator46 engages an o actuator cam 43 to rotate operatory 40 a fraction of acomplete turn. Consequently, operator cams 44 are also rotated to adegree such that blade 14 drops oi the edge of the cam surface. In doingso, blade 14 moves to a position tending to separate the contact 16 fromcontact 17, thereby opening the switch. Because of the deflectionagainst the resilient bias of both blades when in the switch closedposition, blade 15 tends to follow blade 14. However, because of theunequal lengths of the switch blades, the spacing of the operator cams,blade 15 is prevented from following blade 14 to its completedeflection. Thus, blade 15 comes into engagement with a leading operatorcam 44 while blade 14 drops `offto engage a trailing operator cam. Toachieve the accuracy of operation desired in such switch action, theangular and circumferentiail spacing of the cam surfaces, -as well assuitable contours thereof, must be controlled within a reasonabletolerance. It has been found that this can be very easily achievedthrough the unitary construction of the operator. Furthermore, theunitary construction assures xed relative position of the cams therebyimproving reliability in usage.

It will be noted that, during the operation of the switch blades, theycontinue to exert a torque in opposition to the turning torque suppliedfrom the actuator elements 35 and 36 to actuator cams 42 and 43. Thiscountertorque, while appreciable to cause reverse rotation of operator40, is considerably less than that required of prior devices using morecomplicated structures. Therefore, motor 31 and its connected gearingcan be designed from reduced capacity criteria to realize a saving inspace and other manufacturing costs.

If the counterrotary torque were allowed to act, switch operator 40would be reversed some angular distance from that to which it wasadvanced through action of the actuator elements on the actuator cams.This condition, if allowed to exist, would affect the accuracy ofalignment of the cams and would further affect certainty of switchoperation. To overcome these undesirable effects, spring member 45 whichfunctions to retain operator 40 on shaft 13 does so by bearing againstthe end of operator 40 and imposing a resistance to rotation thereof.Counterrotation is assured within reasonable limits permitting easyrotation of operator 40 by the drive mechanism when protrusion 48 onspring member 45 rides into circumferentially arranged recesses 47 asoperator 40 is rotated in its successive angular advances duringswitching. Because of the arrangement of the parts to provide a 4freeend shaft support, easy access to the spring member 45 for adjustment ofspring tension and positioning is provided. Thus, the effectiveness withwhich anticounterrotation is achieved is controllable within limitsconsistent with resistance to rotation from the drive mechanism.

Therefore, while a particular embodiment of the subject invention hasbeen shown and described herein, it is in the nature of descriptionrather than limitation, and it will occur to those skilled in the artthat various chnages, modications, and combinations may be made withinthe province of the appended claims, and without departing either inspiritA or scope from this invention in its broader aspects.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

l. A time switch assembly comprising in combination a support memberhaving an enlarged opening therethrough, a concavo-convex bridge memberacross said opening fixed to said support member, a stationary shaftcarried by said bridge member so as to extend through said opening andbeyond the rear face of said support member, relatively movableswitching elements mounted to the rear of said support member, anactuating device including a timed rotary member mounted to the front ofsaid support member and spaced actuator elements carried thereby, acylindrical operator having longitudinally arranged sets of armsradiating from the peripheral surface thereof, said operator beingrotatably mounted on said shaft and rotated by said actuating devicewithin said opening and the concavity of said bridge member whereby afirst set of said cam means protrudes from said opening in said supportmember to be periodically engageable with said actuator means and asecond set of said cam means is in operative relation with said switchmeans.

2. A time switch assembly comprising in combination a support memberhaving an enlarged opening therethrough, a cup-shaped member integralwith said support member to cover said opening on the front sidethereof, said cup-shaped member having an opening in the side thereofproviding access to the inner realm thereof, a shaft member integralwith said cup-shaped member and extending from the inner surface thereofthrough said enlarged opening, relatively movable switching bladesmounted to the rear of said support member, a timing device including arotatable calibrated timing disc mounted to the front of said supportmember having its peripheral edge proximate said opening in saidcup-shaped member, actuator elements carried by said disc and movingtherewith to describe an arc through said opening in said cup-shapedmember, a cylindrical operator having actuator cams and operating camsdisposed axially along the peripheral surface of said operator, saidoperator being rotatably mounted on said shaft and positioned to havesaid actuator cams within the inner realm of said cup-shaped member soas to radiate outwardly through said opening in the side thereof forengagement with and rotation by said moving actuator elements, saidoperator cams being in operative relation with said blades, and meansattached to the free end of said shaft for holding said operator inoperating position.

3. A time switch assembly comprising in combination a support platemember having an enlarged opening therethrough, a cup-shaped memberintegral with said support plate member to cover said opening on thefront side thereof, said cup-shaped member having an opening in the sidethereof providing access to the inner realm thereof, a shaft memberintegral with said cup-shaped member and extending from the innersurface thereof through said enlarged opening beyond the rear face ofsaid support member, relatively movable switching blades mounted to therear of said support member, a timing device including a rotatablecalibrated timing disc mounted to the front of said support memberhaving its peripheral edge proximate said opening in said cup-shapedmember, actuator elements carried by and extending beyond the edge ofsaid disc and moving therewith to describe an arc through said openingin said cup-shaped member, a cylindrical switoh operator having actuatorcams and operator cams disposed axially along and integral with theperipheral surface of said operator so as to radiate therefrom, saidoperator being rotatably mounted on said shaft and positioned to havesaid actuator cams Within the inner realm of said cupshaped member so asto radiate outwardly through said opening in the side thereof forengagement with and rotation by said moving actuators, said operatorcams being in operatively wiping engagement with said deflectableblades, and. means attached to the free end of said shaft for holdingsaid operator in operating position.

4. A time switch assembly comprising in combination a support memberhaving an enlarged opening therethrough and a bridge member on one sidethereof spanning said opening, a stationary shaft centrally disposedwithin said opening having one end connected to said bridge member andthe other end freely extended beyond the opposite side of said supportmember, a timing device including a rotatable disc on one side of saidsupport member and actuator elements carried thereby, deectable switchelements on said support member on the side opposite said rotatabledisc, a unitary switch operator rotatably mounted on said shaft, saidoperator having cam means for operatively engaging said actuatorelements and said switch blades, said operator being rotated by means ofsaid actuator elements, and means attached to the free end of said shaftfor retaining said operator in operative position.

5. A time switch assembly as in claim 4 in which said support memberincluding said bridge member and said stationary shaft are formed as aunitary piece.

6. A time switch assembly as in claim 4 in which said cam means isformed integral with said cylindrical operator.

7. A time switch assembly as in claim 4 in which said support memberincluding said bridge member and said Shaft are made as a unitary pieceand said cylindrical Cil operator has said cam means formed integralwith the outer surface thereof.

8. A time switch assembly as in claim 4 in which said retaining means isan anticounterrotation element.

9. A time switch assembly as in `claim 4 in which said cylindricaloperator has circumferentially disposed recesses on the end thereof andsaid retaining means com` prises a resilient member biased intoengagement with the end of said cylindrical operator, said resilientmember having a protrusion for riding into and out of said recesses assaid operator is rotated on said shaft.

10. A time switch assembly comprising in combination a support memberhaving an enlarged opening therethrough and a bridge member on one sidethereof spanning said opening, a stationary shaft centrally disposed insaid opening having one end xed to said bridge member and the other endfreely extending beyond the opposite side of said support member, aunitary switch operator rotatably supported by said shaft, said operatorhaving integral cam means on the outer peripheral surface thereof, atiming device including a rotatable disc on one side of said supportmember and a plurality of actuator elements carried thereby forperiodically engaging certain of said cams to impart rotation to saidoperator, resilient switch elements on said support member on the sideopposite said rotatable disc, said switch elements being in biasedengagement with certain other of said cam means, said switch elementsimposing a net bias torque on said operator, and resilient meansattached to the free end of said shaft biased into engagement with theend of said operator to resist counterrotation due to said bias torque.

References Cited in the tile of this patent UNITED STATES PATENTS2,146,562 Cameron et al. Feb. 7, 1939 2,488,110 Aitken Nov. 15, 19492,624,812 Shaw et al. Jan. 6, 1953 2,658,573 Harris Nov. 10, 19532,671,830 Gallagher et al. Mar. 9, 1954 2,690,526 Morrison Sept. 28,1954 2,742,538 Grandstaff Apr. 17, 1956

